algorithmic modeling for Rhino
Good reminder of the Shatter component too!
Good call Ethan. That revolved ellipse was a nasty surface!! NOTHING would intersect with it. Even with Ethan's fix, it's still not a "Closed Brep" so I'm surprised that 'SDiff' works. Here is a 'SrfSplit' approach, one of several intersection methods that all failed with the original 'RevSrf'. It has a test sphere in addition to the ellipse.
I always have issues with revolved surfaces!
Its the seams, happens often with spheres also. Even just in rhino things get weird if you say.. try and draw a curve on surface across the seam - it usually wants to go the opposite direction.